Field of the Invention
The present invention relates to a method for making optical waveguides and more particularly to a method of making an optical waveguide preform.
Description of the Prior Art
In EP-A2-0 153 619 corresponding to U.S. Pat. Nos. 4,620,862 and 4,661,136 there is disclosed a method of fabricating a preform wherein pulverulent material is filled into a mold under pre-compaction using a screw conveyor. The conveying speed, or, more precisely, the quantity of pulverulent material conveyed per unit of time, is determined by the speed of the screw conveyor.